What Is “Emer Heat” on a Thermostat?
The “Emer Heat” setting on your thermostat activates the auxiliary or emergency heating system, providing supplemental heat when your primary heating source (usually a heat pump) is unable to keep up. It’s designed for temporary use during extreme cold or system malfunctions.
Understanding Emergency Heat: The Basics
Many modern homes, particularly those in moderate climates, rely on heat pumps for both heating and cooling. Heat pumps efficiently transfer heat from one place to another. However, their efficiency decreases significantly in very cold temperatures. That’s where the “Emer Heat” setting comes in. It bypasses the heat pump and utilizes a separate, usually electric resistance, heating system.
Why You Have “Emer Heat” (And Why It Matters)
The presence of an “Emer Heat” setting signifies that your home is equipped with a heat pump system. Understanding its purpose is crucial for efficient home heating and preventing unnecessary energy costs.
- Primary Heating System: The heat pump – your first line of defense.
- Secondary Heating System: “Emer Heat” – your backup in emergencies.
- When to Use It: Only when the heat pump is demonstrably failing or during extreme cold spells where the heat pump simply can’t keep up.
- Why It Matters: Misusing “Emer Heat” can lead to dramatically higher electricity bills.
How “Emer Heat” Works
When you select “Emer Heat” on your thermostat, you’re essentially telling the system to completely ignore the heat pump. Instead, it directly activates the auxiliary heating coils or strips located within your air handler. These coils function like a giant toaster, generating heat through electrical resistance. While effective, this process is significantly less energy-efficient than the heat pump.
Here’s a simplified breakdown:
- Thermostat Call for Heat: Your thermostat senses the room temperature is below the setpoint.
- “Emer Heat” Activation: You manually select the “Emer Heat” option.
- Heat Pump Bypassed: The heat pump is effectively disabled.
- Auxiliary Heat Activated: Electric resistance coils are energized.
- Warm Air Distributed: The blower fan circulates the heated air throughout your home.
Recognizing When to Use “Emer Heat”
Knowing when to engage “Emer Heat” is just as important as knowing what it is. Avoid using it unless absolutely necessary.
- Extreme Cold: If the outside temperature is well below freezing and your heat pump struggles to maintain a comfortable temperature, “Emer Heat” can provide supplemental warmth. However, ensure your heat pump is actually running first.
- Heat Pump Malfunction: If your heat pump is visibly broken (e.g., making strange noises, not blowing warm air), engage “Emer Heat” until repairs are made.
- Icing Issues: Excessive ice buildup on the outdoor heat pump unit can sometimes warrant using “Emer Heat” temporarily to allow the unit to defrost. However, a properly functioning heat pump should be able to defrost itself.
Common Mistakes to Avoid
The most common mistake is relying on “Emer Heat” as the primary heating source. This can lead to shockingly high energy bills. Other errors include:
- Ignoring the Heat Pump: Assuming the heat pump isn’t working without properly troubleshooting.
- Leaving “Emer Heat” On: Forgetting to switch back to the regular heating mode after the extreme cold has passed or the heat pump is repaired.
- Ignoring Icing Issues: Failing to address the underlying cause of excessive ice buildup on the heat pump, leading to frequent and unnecessary “Emer Heat” usage.
Troubleshooting Heat Pump Issues
Before resorting to “Emer Heat,” try these basic troubleshooting steps:
- Check the Thermostat: Ensure the thermostat is set correctly and the batteries are fresh.
- Inspect the Outdoor Unit: Look for obvious obstructions (e.g., snow, ice, debris) around the heat pump.
- Check the Air Filter: A dirty air filter can restrict airflow and reduce heat pump efficiency.
- Restart the System: Try turning the system off and on again at the breaker.
What does “Emer Heat” mean on my thermostat?
“Emer Heat” stands for Emergency Heat. It’s a setting that activates the auxiliary or backup heating system in your home, usually electric resistance heat, bypassing the more efficient heat pump.
When should I use “Emer Heat”?
Use “Emer Heat” only when your heat pump is malfunctioning or during periods of extreme cold when the heat pump cannot maintain a comfortable temperature.
Is “Emer Heat” more expensive than using my heat pump?
Yes, “Emer Heat” is significantly more expensive to operate than a heat pump because it relies on electric resistance heating, which is less energy-efficient.
How do I know if my heat pump is not working properly?
Signs of a malfunctioning heat pump include blowing cold air when set to heat, making unusual noises, and not maintaining the set temperature.
Can I leave “Emer Heat” on all the time during the winter?
No. Leaving “Emer Heat” on continuously will result in very high energy bills. It is designed for emergency or short-term use only.
What’s the difference between auxiliary heat and “Emer Heat”?
In most cases, auxiliary heat and “Emer Heat” refer to the same thing: the backup electric resistance heating system. Some systems may use “auxiliary heat” in conjunction with the heat pump during defrost cycles or periods of moderately cold weather, while “Emer Heat” completely disables the heat pump.
My thermostat says “Aux Heat On.” Is that the same as “Emer Heat”?
Not necessarily. “Aux Heat On” could indicate that the auxiliary heat is supplementing the heat pump, while “Emer Heat” signifies that the heat pump is completely disabled and only the auxiliary heat is operating. Check your system manual for specifics.
What should I do if my heat pump keeps switching to “Emer Heat” automatically?
If your heat pump is frequently switching to “Emer Heat,” it indicates a potential problem with the heat pump itself, such as a refrigerant leak, compressor issue, or defrost control malfunction. Call a qualified HVAC technician for diagnosis and repair.
Will using “Emer Heat” damage my heating system?
Using “Emer Heat” itself won’t typically damage your system, but prolonged or unnecessary use can put extra strain on the electrical components and increase wear and tear.
How can I lower my energy bills if I have to use “Emer Heat”?
If you must use “Emer Heat,” lower the thermostat setting slightly to minimize its runtime. Also, ensure your home is well-insulated to reduce heat loss. Address the underlying issue causing the heat pump to fail.
Can I install a heat pump if I currently have only electric resistance heating?
Yes, you can install a heat pump to replace electric resistance heating. This can significantly reduce your energy consumption for heating, especially in moderate climates.
Where is the “Emer Heat” setting located on my thermostat?
The “Emer Heat” setting is usually found on the main control panel of your thermostat. It might be a button, a switch, or an option in the menu. Consult your thermostat’s user manual for specific instructions.